The invention relates to multi-mode radiator panels, in particular to supplying and processing signals for multi-mode radiator panels.
Multi-mode radiator panels for radiating sound are known in the art and include essentially a flat sound panel which is driven by at least one electrodynamic driver connected to the sound panel. Further details relating to the design and operation of such multi-mode radiator panels are disclosed, for example, in the patent DE19757097 and DE19757098 which relate to the subject matter of the present invention.
If such multi-mode radiator panels are used to reproduce sound, then a respective driver electronics has to be provided for processing the received and generated sounds signals before these are supplied to the drivers. The multi-mode radiator panels operating in this fashion can be employed as individual sound reproduction devices. More often, however, the multi-mode radiator panels are used as so-called xe2x80x9cacoustic wallsxe2x80x9d and include a plurality of multi-mode radiator panels which are arranged side-by-side and connected to each other. Conventionally, the driver electronics is essentially formed of an amplifier and filters integrated in the respective signal paths. With this technique, however, the technical specification of the different individual components disadvantageously have to be oversized to provide versatility for different applications. Since the drivers have to supply approximately 10 to 100 watts of power, special connectors for the signal paths, extremely low loss cables, expensive shielding, large power reserves and large tolerances of the impedances may be required depending on the application.
It therefore would be desirable to provide a multi-mode radiator panel which requires a less complex driver electronics.
According to one aspect of the invention, the entire driver electronics is integrated in the air space of the respective multi-mode radiator panel. In this way, the multi-mode radiator panels can be connected easily with one another and/or with a signal source receiving or generating the acoustic signals. Alternatively or in addition, each of the multi-mode radiator panels, which are combined to form an acoustic wall, may have the entire driver electronics in the air space. In the case of multi-mode radiator panels of an acoustic wall which is be optimized for radiating sound at high frequencies, the entire driver electronics may be distributed over the air space of the multi-mode radiator panels radiating sound over this frequency range. It is particularly advantageous if the mounting devices which connect the multi-mode radiator panel with the frame, hermetically enclose the air space enclosed between the frame and the multi-mode radiator panel, since then the multi-mode radiator panel and the driver electronics located in the air space may then also be operated without problem in listening areas which pose an explosionxe2x80x94hazard or are subjected to a hostile environmental and/or climate.
The driver electronics referred to in this application includes the audio electronics, which includes the power amplifier and associated filters for separating the various frequencies or frequency ranges, and the communication electronics which connects the electronics with an acoustic signal source and/or connects different multi-mode radiator panels with each other, if several multi-mode radiator panels are combined to form, for example, an acoustic wall. The communication electronics also forms, when a command dialog is entered, the interface between commands entered by a user and the driver electronics and/or a multimedia center connected to the multi-mode radiator panel. The driver electronics also includes a battery buffer which is connected to the remaining driver electronics. It will be understood by those skilled in the art that the driver electronics need not include all the above-referenced components. In other words, for example, the battery buffer need not be implemented if the power supply is able to satisfy peak power requirements.
According to one embodiment of the invention, the driver electronics may include a power amplifier matched to a respective driver. In this case, the power amplifier can be optimized for that driver. Unlike in conventional driver electronics, where an individual amplifier typically powers one or more drivers and where the amplifier and the drivers are often configured by the end-user, the power amplifier according to the invention need not include reserve power since the amplifier and the driver form a matched unit. Implementing the amplifier and the driver as a matched unit has the additional advantage that the different components are matched and can therefore be optimized with respect to each other, thereby reducing the likelihood of damage to the unit.
According to another embodiment of the invention, the driver electronics may include electronic filters either in analog or digital form. The power amplifiers and associated drivers can then be used in a cost-effective way to separate the different frequencies. This arrangement advantageously eliminates the power electronics required by conventional devices for separating the frequencies.
According to yet another embodiment of the invention, the driver electronics is powered by a DC power source. With this arrangement, the electric power and the acoustic signal can be supplied over common wires which connect the driver electronics to the acoustic signal source. In addition, unlike power amplifiers powered through the high-voltage mains, the low-voltage power supply according to the invention does not pose a hazard if plugs or receptacles are left unprotected.
According to still another embodiment of the invention, an additional power source for supplying peak power which may be required by drivers operating at low frequencies, can be eliminated by integrating in the air space a battery with a charging electronics powered by DC, wherein the battery supplies the required peak power. In addition, a capacitor may be connected in parallel with the battery to faithfully reproduce infrequently occurring short high-power spikes with low distortion. Buffering with a battery also ensures that the multi-mode radiator panels remain operational during emergencies, for example, during an interruption of the DC power supply, which can aid in securing escape routes. The charging electronics may be designed to prevent the charge state of the battery from dropping below a critical charge state which may occur, for example, when peak power is required over an extended time period. In this case, the acoustic volume may be automatically adjusted with dynamic compensation in when such low charge state is reached.
According to another embodiment of the invention, the (first) interface which connects the driver electronics with the acoustic signal source, may be implemented as a bus-enabled interface. With this arrangement, a multi-mode radiator panel can be operated wherever a corresponding bus is provided. In other words, if bus technology is available, the multi-mode radiator panel can become the sole end device.
According to yet another embodiment of the invention, the bus connected to the multi-mode radiator panel may also include the power supply system, if the respective power amplifier is powered by a DC power source. This arrangement provides for a flexible operation of the multi-mode radiator panel.
According to still another embodiment of the invention, a second interface may be provided for interconnecting several multi-mode radiator panels in form of a network and/or for receiving and transmitting a command dialog. The multi-mode radiator panels can thereby communicate with the power amplifier and/or a multimedia center via the second interface. For sake of flexibility, this communication channel may be wireless and implemented, for example, in infrared technology.
Further features and advantages of the present invention will be apparent from the following description of preferred embodiments and from the claims.